Sometimes when you present something new to certain people, the first thing they want to do is modify it (often to make things easier for them). Listen; there is nothing wrong with modification which is something that I always encourage people to do especially when getting acquainted with the moves and different routines. However, I feel there is a difference between choosing whether to do a one-hand push on your knees versus changing the order of videos on your calendar or skipping a video altogether.
Change is important and it is the principle behind muscle confusion. However, when you start making significant changes to the schedule, unless you are perfectly sure what you are doing, you can actually hurt your chances of success. P90X is designed so you have three lift days interspersed with other core/cardio videos. It is always my recommendation that people stick to the calendar, be it the classic, lean or double routine. If you are an expert in exercising and really know what you are doing, then go ahead and do it, but quite honestly, for the majority of people I coach and deal with on a daily basis, sticking to all aspects of the program is really what makes you succeed.
The problem with changing your schedule dramatically is that often people think they know what they are doing, when in fact, they don’t. They are still stuck in the same ways of thinking prior to starting the program and because they are building muscles and since weight loss is sometimes not completely visible (due to added muscle mass), they revert back to their old routine or modify the program thinking that’s why they need to do in order to get results. You need to give you body time to adjust to the nutritional plan and the exercises. Patience is a virtue and it applies here too!
When you do P90X, you have one rest day or stretch day which typically falls on a Sunday. If you are really inclined to modify the schedule, I’d still stick to the original three lift days giving the proper 48 hours for all muscles to heal because muscle grows when you rest, NOT when you are pumping iron! By the way, one thing you can do and it is quite simple is the following: You DON’T have to start exercising on a Monday. Maybe you want to modify the begin date so Yoga X falls on Saturdays or Sundays (since it is the longest video at nearly 90 minutes in length). This is an easy beginner fix.
Another change that I reluctantly recommend is splitting AB Ripper X from the other videos. If you are faced with a schedule where exercising another video back to back is impractical, I’d rather you do it some other day or split them up versus not doing AB Ripper X at all. AB Ripper X is not about giving you a six pack, it is about strengthening your core so you are less prone to injuries, so you have better posture, no back pain, I mean, it is VERY important. I am not saying saying having a six pack is not important. It is just not the primary goal of the video. It is sort of a “side-effect”. (I can only wish every medicine had that kind of side effect).
Once you have graduated from P90X and are more knowledgeable about the program you can start adding other videos and routines if you have achieved a fitness level adequate to push even further. Tony says that variation is the spice of life so one of the suggestions I typically give P90Xers when they reach a point where they want to challenge themselves or add a more intense cardio is to begin incorporating videos from the amazing One on One Series or something like Insanity which allows some people (myself included) to burn over 1000 calories).